Semiconductor devices, such as Integrated Circuits (IC's) are commonly found in electronic consumer products. IC's include a plurality of contacts for interconnection with circuit boards and other electronic components. The contacts are secured to a circuit board (i.e., package substrate) either directly or through an interposer. An interposer is an interface substrate that can be used to pass signals directly between, or to spread or otherwise reroute, connections from the IC to connections on a circuit board or another IC. Use of the interposer allows for a high density of connections on the IC to be distributed in a desired architecture across another component (e.g., circuit board).
As many modern devices have mounting space restrictions, some devices utilize a flip-chip method for interconnecting an IC to external circuitry. Flip-chip IC's include solder micro-bumps that have been deposited onto various contact pads on the IC. The contact pads are interconnected with the internal circuitry of the IC. The solder micro-bumps are deposited on the contact pads on the top surface of the IC during processing. With the solder micro-bumps in place, the IC can then be mounted on top of a mating component (e.g., circuit board, an interposer, or another IC), thereby reducing the size of the surface area needed on the mating component.
Mounting a flip-chip IC involves flipping it over so that the top surface of the IC (having the solder micro-bumps) can be placed over the mating component to align the solder micro-bumps with associated contact pads on the mating component. The solder is heated (i.e., reflowed) to complete the connection between the flip-chip IC and the mating component. Prior to installation of the flip-chip IC, the flip-chip IC is typically tested to identify any defects. The flip-chip IC can include various testing points that are configured to be contacted with a test probe for performing suitable testing of the flip-chip IC. The solder micro-bumps include a very fine pitch, which can be easily damaged when contacted by a rigid object. Therefore, to accommodate the test probe, test probe pads are interspersed among the contact pads to provide testing points. During testing, the test probe is extended downwards to contact one or more test probe pads to provide an electrical connection between the test probe and one or more circuits on the flip-chip IC.